Does Google Maps assume I'm speeding when giving me estimated time of arrival?

That algorithm can’t figure out 12 min is more than 10 min and that there isn’t currently any issue with traffic?

I think part of it is a “No, you aren’t smarter than Google” feature. People watching their GPS and going “You know, I bet if I exit here I’ll save some time.” So Google already adds the alternate route in showing you that, no, it’s going to take longer. Sometimes it’s just a little screw and the alternate route is just a big loop.

Google does that all the time while you’re driving. Any time you’re coming up on a turn that can get you to your destination in a similar amount of time, it throws it up as an ETA. It’s just that it doesn’t realize the “alternate route” in these cases is literally just a loop on and off the ramps. It would be easy enough for the developers of the app to say “don’t give these alternate ETAs if the driver is on an interstate,” so I have to imagine there’s a perceived value.

It could just be as simple as, “Hm, if I pull off here to get some coffee, it’s only two extra minutes of drive-time to make it back onto the road.”

No sane person would get off the highway and get right back on there. It’s not a human way to “beat Google.” (And it is possible to find a faster route than Google as it will understandably often not route you through residential side streets.)

Actually, I can’t tell for sure from the image you posted whether the gray route assumes you were originally on the highway, or on a frontage road that runs alongside it.

I have had cases where the ETA could not possibly have been based strictly on the speed limit, i.e. cases where the distance/ETA averaged above the speed limit. But those have typically been for longer (200-400 mile Interstate) drives. And, yeah, when I’m a bit bored on long drives, I like to do simple arithmetic to keep the mind occupied.

In-city, it tends to be pretty accurate, give or take the vagaries of local traffic.

So, prevailing traffic and/or historic user patterns almost certainly are part of the estimates, and sometimes those are somewhat above the speed limit. I would imagine speed limit is part of the algorithm but certainly not the only or even the prevailing part.

Some of this is also the fact that Google isn’t really all-knowing. There are several instances where it does not know the speed limit completely accurately (most noticeable in construction zones but also just generally true on some stretches of highway), and this can swing things by a few minutes sometimes.

Good point. I don’t have a greater conetext for that screenshot. If that’s the case, why suggest the longer route? It’s not “avoid highways” as it puts you on the highway anyway.

It’s not a suggestion. It’s information. It’s just saying, “hey, if you turn here it’ll be 12 minutes instead of 10 minutes.”

Another on I get is where I’m going, say, north on a road and it suggest me turn right, go a block, turn left, go a block, turn another left, go a block and end up back on the road as I was on, with “similar ETA.” And this is not a road with traffic — just stop signs. I don’t have a picture of that one, but similar happens intermittently to me and I could find no rhyme or reason to it as it seems so completely arbitrary when it tells me of pointless alternate routes and when it just shows the primary route.

Because it’s pointless info. It can nag me all the way to my destination with alternate routes if it wanted to give me “information.” I have no interest in seeing a route that is “18 minutes slower” mid-route (also happened). Why would I want that info?

It’s called a pit stop - Google has calculated that you might just need to stop for a moment at this point in the journey.

Doesn’t Google Maps always offer two alternative routes? (Perhaps not while en route but at least during the “planning stage” – i.e., before you hit START.)

I picture the lucridous alternative routes as a sort of “malicious compliance” on the part of the computer. “OK, programmers, if you insist I show an alternative – even when I know there is no better way – then here you go!”

On a ten minute drive? How old does Google think I am?

On my cross country trips I’ve had Google tell me to take an exit for a frontage road and then get back on the freeway a mile later. One time it tried to divert me through a truck weigh station.

My biggest peeve is when Google routes me through an endless series of rural back roads because it’s faster than taking a freeway. Faster maybe, but sometimes those routes take you way out into the boonies. I once spent almost a full day on county and ranch roads in Texas between Waco and Fort Stockon, wondering where the heck I was most of the time.

Who knows? Maybe you like taking different routes now and then. Maybe you’ve been stuck behind a bus for a half-mile and want to detour. Maybe it’s late at night and you happen to know an upcoming stretch of road doesn’t have good lighting. Maybe you’re feudin’ with the guy who owns the Chicken Shack and don’t want to drive past the restaurant because he keeps throwing chicken necks at your car.

There are a million reasons why somebody may say, “Hm, I wonder if it’ll take longer if I turn here,” but since they’re in the middle of driving they can’t/shouldn’t go poking at their phone. So it’s helpful to have it right there.

It’s just data. You can do what you want with it, or nothing at all. Its lack of value to you, though, doesn’t make it universally valueless.

They suggested you do that before you left - maybe it knows you don’t always listen.

I’m mostly talking about alternative routes that show up while driving, like when they suddenly appear as an alternate route you didn’t ask for. Now when it saves me time, sure, light it up. But telling me I can make a right, two lefts, and a right to go straight on a road that is traveling at normal speeds is just weird to me.

But it seems completely arbitrary when it does it. When I’m three blocks from my destination, I don’t need an alternate route to go straight, and I have a hard time thinking of anyone who would.

As I said, in my experience it isn’t arbitrary. It’s any time a turn would result in a similar ETA. Google isn’t presuming to guess what you might or might not find useful.

I’m not sure what the underlying mapping software is for Subaru, but there was a curving section on I 95 where the map regularly tried to get me to get off the highway and then back on again. It eventually stopped, but I have no idea what that was about.